GradedHealth

Do nuts lower cholesterol? Trials show a small LDL drop

Pooled trials show eating nuts lowers 'bad' LDL cholesterol a little. Heart-attack benefit is not established, and the trials did not measure it.

Published October 2026

Short answer

Nuts lower LDL ('bad') cholesterol a little in trials. That is a blood marker, not proof of fewer heart attacks, so the evidence is limited. Evidence grade C (Limited). Pooled trials of 113 studies show a small LDL drop; downgraded for a surrogate marker and for inconsistency, since a 2023 GRADE rating of LDL evidence is very low.

Key takeaways

  • Across 113 trials of about 8,060 adults, eating nuts lowered LDL cholesterol by about 0.12 mmol/L compared with a non-nut diet [1].
  • LDL is a blood marker: the trials in the 2015 Cochrane review did not measure heart attacks or other heart events [2].
  • In cohort studies, people who ate the most nuts had a lower risk of dying from coronary heart disease, but cohort studies cannot prove that nuts caused the difference [3].
  • Nuts did not cause weight gain in trials, in trials lasting more than three weeks [4].
  • Tree nut allergy can be serious, usually starts in childhood and often lasts for life [5].

The short version

Do nuts lower cholesterol? A little, in trials. A 2025 review of 113 randomised trials found that eating nuts lowered LDL ("bad") cholesterol by about 0.12 mmol/L compared with a diet without nuts [1]. Whether nuts reduce heart attacks is not yet established: the trials in a 2015 Cochrane review did not measure heart events, and the studies that link nuts to fewer heart deaths are observational [2][3].

What the studies show

The 2025 review pooled 113 trials with 8,060 adults. The nuts were given at a median of 45.5 grams a day [1]. Total cholesterol fell by about 0.14 mmol/L and triglycerides by about 0.05 mmol/L. HDL, the "good" cholesterol, did not change significantly [1].

An earlier 2015 meta-analysis of 61 trials put the effect per daily one-ounce (28 gram) serving: LDL fell by 4.8 mg/dL, and the effect was stronger at 60 grams or more a day [6]. Those trials ran for 3 to 26 weeks [6].

Heart events are the outcome that matters, and trials have not measured them well. The 2015 Cochrane review found no trial that reported heart attacks or other clinical events, and it judged the trials small and short [2]. A 2016 meta-analysis of 20 prospective cohort studies, with about 467,000 people, found a lower risk of dying from coronary heart disease among people who ate the most nuts, with a risk ratio of 0.70 [3]. Cohort studies can show an association, but not cause and effect [3].

Nuts do not appear to add weight. A 2021 meta-analysis of 55 trials found no change in body weight [4]. A 2022 review of 15 trials in people with type 2 diabetes also found no effect on body weight or body fat [7].

The nuances

Nuts are energy-dense, but the energy the body absorbs from them appears lower than standard calorie values predict [8]. The review says this may help explain why nut intake is not linked to weight gain, while noting that the methods varied between studies [8].

The evidence is not uniform. A 2023 review of tree nuts and peanuts rated the LDL evidence as very low certainty because of inconsistency and possible publication bias [9].

Funding matters here. One author of the 2025 review reports ties to nut industry groups, including the Almond Board of California and the International Nut and Dried Foundation. The review states that these groups had no role in the study [1]. A 2025 review of almond trials found LDL fell by about 0.13 mmol/L. It was funded by the Almond Board of California, and its authors work for a firm paid by the Board [10].

The Cochrane review included trials of healthy adults and of adults at moderate or high risk of heart disease [2]. Studies in people with chronic kidney disease are few: a 2025 review of four studies (three trials and one cohort) found walnuts lowered LDL and posed no electrolyte risk, but all four had moderate-to-high risk of bias [11].

Safety: tree nut allergy usually starts in childhood, rarely fades and is one of the main causes of serious allergic reactions [5]. One trial in the Cochrane review reported an allergic reaction to nuts [2]. The reviews above do not report on pregnancy or breastfeeding, so they offer no evidence for those groups [2].

What this means for you

The 2025 review's trials used a median of 45.5 grams a day [1], and stronger LDL effects were seen at 60 grams or more a day [6]. The effect on cholesterol is modest and the evidence is limited, so nuts are best seen as one part of an eating pattern, not a treatment for high cholesterol. Anyone with a nut allergy should avoid nuts [5]. People with kidney disease, or who take cholesterol-lowering or blood-thinning medicines, should talk to a doctor before changing their diet.

Go deeper

  • Nuts — Nuts lower LDL cholesterol a little in trials and, in trials lasting more than three weeks, do not appear to cause weight gain.

References

  1. Effect of nut consumption on blood lipids: An updated systematic review and meta-analysis of randomized controlled trials.. Nutr Metab Cardiovasc Dis, 2025.
  2. Nut consumption for the primary prevention of cardiovascular disease.. Cochrane Database Syst Rev, 2015.
  3. A systematic review and meta-analysis of nut consumption and incident risk of CVD and all-cause mortality.. Br J Nutr, 2016.
  4. Intake of Nuts or Nut Products Does Not Lead to Weight Gain, Independent of Dietary Substitution Instructions: A Systematic Review and Meta-Analysis of Randomized Trials.. Adv Nutr, 2021.
  5. Tree nut allergy.. Postepy Dermatol Alergol, 2021.
  6. Effects of tree nuts on blood lipids, apolipoproteins, and blood pressure: systematic review, meta-analysis, and dose-response of 61 controlled intervention trials.. Am J Clin Nutr, 2015.
  7. Nut consumption, body weight, and adiposity in patients with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials.. Nutr Rev, 2022.
  8. The Metabolizable Energy and Lipid Bioaccessibility of Tree Nuts and Peanuts: A Systematic Review with Narrative Synthesis of Human and In Vitro Studies.. Adv Nutr, 2023.
  9. Tree Nut and Peanut Consumption and Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.. Adv Nutr, 2023.
  10. Blood Lipid Levels in Response to Almond Consumption: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.. Nutrients, 2025.
  11. Nut consumption in chronic kidney disease: a systematic review.. Front Nutr, 2025.